Function-as-a-Service (FaaS) is a cloud computing model that allows developers to execute individual functions or code snippets without having to worry about the underlying infrastructure. Essentially, FaaS enables developers to upload and run code in the form of functions without dealing with the deployment, scaling, or management of server infrastructure.

The idea behind FaaS is that developers only need to write and upload the code that fulfills a specific function. The FaaS platform then handles the execution of this code when triggered by events or requests. A typical example of FaaS is using serverless computing in the cloud, where developers deploy functions in the cloud that run only when needed.

Popular FaaS platforms include AWS Lambda by Amazon Web Services, Azure Functions by Microsoft Azure, and Google Cloud Functions by Google. They allow developers to upload and execute code in various programming languages, simplifying application development and scalability without worrying about the underlying infrastructure.